JP2017048087A - Method and apparatus for producing hydrogen from fossil fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogen production method capable of producing high purity hydrogen from fossil fuel at a low cost, and a production apparatus used for the method.SOLUTION: A partial oxidation (gasification) method capable of using low quality fossil fuel, such as brown coal and heavy oil, as a raw material is adopted as a method for producing hydrogen from fossil fuel, and hydrogen rich gas contained in gas having been subjected to gas purification, CO shift, dehumidification, desulfurization, and CO2 separation is purified by a cryogenic separation method to obtain high purity hydrogen. Liquid nitrogen by-produced when oxygen supplied as a combustion improver for the fossil fuel in a step of partial oxidation is produced by the cryogenic separation method is used as a cold heat medium used for the cryogenic separation method. By the present method, in a method for producing high purity hydrogen from low-quality fossil fuel, high purity hydrogen can be obtained at a low cost without requiring installation of a large-scale auxiliary machine and energy supplied from the outside.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing high-purity hydrogen from fossil fuel and a production apparatus thereof, specifically, after partial oxidation of fossil fuel, it is converted into a gas mainly composed of CO2 and H2 in a shift step, The present invention relates to a hydrogen production method and apparatus for producing high-purity hydrogen by purifying a hydrogen-rich gas by separating the CO2 and H2 by deep-cold separation using a cooling medium.

  In recent years, the importance of hydrogen infrastructure using hydrogen as a primary energy source has been raised from the viewpoint of fossil fuel depletion and global warming prevention. In particular, technological development related to fuel cells has been accelerating in recent years, and household fuel cells such as fuel cell vehicles and ENE-FARM are becoming more popular. Hydrogen used in fuel cells is required to have a high purity of 99.99% or more. Currently, the cheapest and most practical production method of hydrogen gas is the steam reforming method disclosed in Patent Document 1. In this method, fossil fuels such as natural gas and kerosene are used as raw materials, steam is added to these, reformed by the reaction shown in Formula (1), and the generated CO is further subjected to shift reaction in Formula (2). This is a method for producing hydrogen simultaneously with conversion to CO2.

  The hydrogen production method using the steam reforming method has already been established, and it is an effective technology because it has a large number of plant operations. In recent years, the price of natural gas (LNG) has risen due to the influence of the shale revolution. In the future, the production price of hydrogen is expected to rise accordingly. As a hydrogen production method other than the steam reforming method, there is a partial oxidation method of fossil fuel.

  Specifically, fossil fuels such as coal and heavy oil are reacted with oxygen in a gasifier and partially oxidized to form a gasification gas mainly composed of CO and H2, and then the formula is refined after the gas is purified. This is a method in which CO is reacted with water vapor and converted into CO2 and H2 by the shift reaction shown in (2). The partial oxidation method uses fossil fuel in the same way as the steam reforming method, but the difference from the steam reforming method is that other low quality coals such as lignite and heavy oil and residual oil produced as petroleum refining residue are used. This is because hydrogen can be produced using raw materials that are difficult to be applied to applications.

  Patent Documents 2 and 3 disclose a method of generating electricity with a gas turbine using hydrogen generated through a gas refining, shift process, and CO2 separation process after partial oxidation of coal. The hydrogen produced by this method includes CO that has not been sufficiently converted to CO2 in the shift process. However, if it is limited to power generation, there is no problem because CO is combusted together with hydrogen in the combustor in front of the gas turbine. . However, when applied to a fuel cell, if a large amount of CO is contained in hydrogen, when platinum is used as an electrode catalyst of the fuel cell, CO is adsorbed on the platinum and causes deterioration of the catalyst. Therefore, in addition to the purity described above, the hydrogen used in the fuel cell must satisfy the strict restriction of the concentration of CO contained, specifically, 1 ppm or less. In both the steam reforming method and the partial oxidation method, it is necessary to provide a step of separating H2 and other gases, mainly CO2, in the gas generated until the shift step. However, it is difficult to satisfy the above-mentioned required specifications of the fuel cell only with the CO2 separation step, and usually a hydrogen purification step is provided to remove impurities in the hydrogen rich gas separated in the CO2 separation step.

  Patent Document 4 discloses a method using a pressure swing adsorption (PSA) method as a hydrogen purification step. The PSA method is a method that utilizes the pressure dependency of the adsorption power of a gas contained in a mixed gas. Hydrogen has the characteristic that the pressure dependency of the adsorption force is small compared with other gases, and adsorbs gas components other than hydrogen to the adsorbent in the mixed gas containing hydrogen at high pressure. Separates from difficult hydrogen. This is a method of increasing the purity of hydrogen by repeating adsorption, depressurization, washing, and pressurization as one cycle.

Japanese Patent No. 5255896 Japanese Patent No. 2870929 Japanese Patent No. 3149561 Japanese Patent No. 5280824

  Since the hydrogen purification technology based on the PSA method, which is a conventional technology, can obtain high-purity hydrogen, it can be said that this method is suitable for hydrogen purification for fuel cells. As described above, in the PSA method, adsorption, depressurization, washing, and pressure increase are set as one cycle. Therefore, in order to suppress the purification yield of hydrogen that is constantly generated in the upstream plant (steam reforming, partial oxidation, etc.), it is necessary to prepare at least four adsorption towers and perform each process operation.

  In addition, although depending on the scale of hydrogen production at the plant, it is assumed that a large amount of purification gas containing hydrogen obtained by reforming and partially oxidizing fossil fuels will increase the size of the hydrogen purification process. It is assumed that Moreover, since the compression energy of gas required for periodic replacement | exchange of an adsorbent and a pressure | voltage rise process is needed, we are anxious about running cost taking place.

  Accordingly, an object of the present invention is to provide a hydrogen production method capable of producing high-purity hydrogen from fossil fuel at low cost and a production apparatus used therefor.

  The water tank manufacturing method of the present invention includes a gasification step in which fossil fuel is gasified by partial oxidation with oxygen, a gasification gas purification step, and CO contained in the gasification gas is reacted with water vapor by a shift catalyst. A shift step for converting to hydrogen and CO2, a desulfurization step for removing H2S contained in the gas after the shift, a CO2 separation step for separating hydrogen and CO2 produced in the shift step, and a gas after the CO2 separation are purified In a hydrogen production method including a hydrogen purification step for purifying hydrogen, in the hydrogen purification step, gas components other than hydrogen in the hydrogen-rich gas are separated and separated by a cryogenic separation method using a cold medium. It is characterized by purifying to pure hydrogen.

  According to the present invention, high-purity hydrogen can be produced at low cost from fossil fuels. The generated hydrogen is not only applied to fuel cells, but also used for refining various products such as hydrodesulfurization in oil refineries and in the steel production field. Also, hydrogen, methanol, DME, plastic raw materials, etc. It can also be applied to the field of manufacturing chemical products.

1 is a system flow diagram of the present invention shown in Embodiment 1. FIG. It is a system flow figure of the present invention shown in Example 2. It is a system flow figure of the present invention shown in Example 3. It is a system block diagram of the hydrogen purification equipment of this invention shown in Example 4. It is a system block diagram of the hydrogen purification equipment of this invention shown in Example 5. FIG. 6 is a schematic diagram of a test apparatus shown in Example 6. FIG. 7 is a result of catalyst species dependence of the amount of water vapor added in the shift reaction shown in Example 6. FIG.

  Hereinafter, the present invention will be described in detail.

  Focusing on partial oxidation methods that can apply low-quality lignite and heavy oil as a method for producing hydrogen from fossil fuels, purify hydrogen in gas that has undergone partial oxidation (gasification), gas purification, shift, and CO2 separation processes. As a technology, a cryogenic separation method is applied instead of the conventional PSA method.

  The cryogenic separation method is a method in which a mixed gas is cooled using a cooling medium and separated using a difference in boiling points between the gases. The hydrogen-rich gas after the separation of CO2 contains 95% or less of hydrogen, as well as CO2, CH4, and CO, which is a poisoning component of the fuel cell electrode catalyst, as impurities. The boiling points of hydrogen, CO2, CH4, and CO gases are -249 ° C, -79 ° C, -162 ° C, and -192 ° C, respectively. Hydrogen has a lower boiling point than other gases and can be said to be a gas suitable for purification by cryogenic separation.

  The present invention has the following basic features. Gasification process to gasify fossil fuel by partial oxidation with oxygen, gasification gas purification process, shift process to convert CO contained in gasification gas to water vapor by shift catalyst and convert to hydrogen and CO2 And a desulfurization process that removes H2S contained in the gas after the shift, a CO2 separation process that separates the hydrogen and CO2 produced in the shift process, and a hydrogen purification that purifies the gas after the CO2 separation and purifies the hydrogen. In the hydrogen production method comprising the steps, in the hydrogen purification step, CO2 or CO, CH4 in hydrogen is separated by a cryogenic separation method using a cooling medium, and purified to high purity hydrogen It is.

  In addition, for example, as the cooling medium, it is characterized by using liquid nitrogen that is also generated when oxygen that is supplied as a combustion aid in the gasification process is generated in an air separation process that also applies a cryogenic separation method, High-purity hydrogen can be purified using a utility installed in an existing plant without adding a new auxiliary machine for generating a cooling medium.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

Example 1
FIG. 1 shows an example of the system flow of the present invention. Gasification is performed in the gasification process using heavy oil, residual oil, or coal, which is fossil fuel, in the gasification step, and gasification gas mainly containing hydrogen and CO is obtained. Thereafter, in order to remove residues derived from fossil fuels and water-soluble gas components, gasification gas is sent to the gas purification step to remove the impurities. Thereafter, the gas after gas purification is supplied to the shift step, and the shift gas shown in Formula (2) is reacted with CO in the gas and water vapor to obtain a post-shift gas containing CO2 and H2 as main components. In order to accelerate the reaction in the shift reaction, it is common to supply water vapor with a stoichiometric ratio equal to or higher than the stoichiometric ratio of the formula (2). Therefore, water that has not been used in the reaction remains after the shift step. Therefore, a dehumidification step is provided after the shift step to remove moisture in the gas. The reason will be described later. In this embodiment, the shift process shows an example in which the shift process before desulfurization is applied, and therefore, the gas after the shift process contains several hundred to several thousand ppm of hydrogen sulfide (H2S). When H2S is contained in the gas, there is a concern that H2S is absorbed in the CO2 absorbing liquid used in the subsequent CO2 separation step, thereby reducing the CO2 absorption performance. Therefore, a desulfurization process is provided for the purpose of removing H2S in the previous stage of the CO2 separation process. Thereafter, hydrogen and CO2 are separated in a CO2 separation step. A CO2-rich gas and a hydrogen-rich gas are produced after CO2 separation, but the hydrogen purity in the hydrogen-rich gas is 90 to 95%, and CO2, CO, CH4, etc. are included as impurity substances. In order to purify the hydrogen-rich gas to obtain high-purity hydrogen, the hydrogen-rich gas after the CO2 separation step is supplied to the hydrogen purification step. In the hydrogen purification process, hydrogen is purified by cryogenic separation. Liquid nitrogen is used as a cooling medium used in the hydrogen separation step. The liquid nitrogen used is that which is generated when oxygen is generated from air by the cryogenic separation method in the air separation step. Oxygen generated in the air separation step is supplied to the gasification step and used as a combustion aid for partial oxidation of fossil fuel. Since the cryogenic separation method is used in the hydrogen purification process, if a large amount of moisture is contained in the gas to be purified, the moisture may freeze and clog in the piping. Therefore, it is necessary to completely remove the moisture in the previous dehumidification process. There is.

  The effect of the present embodiment is to purify hydrogen using the cold heat of liquid nitrogen produced in the air separation process, which is an essential process in the partial oxidation method of fossil fuel, and newly generate a cold heat source. As a result, it is possible to omit auxiliary equipment and power for the purpose, and to reduce the production cost of high-purity hydrogen.

(Example 2)
FIG. 2 shows another example of the system flow of the present invention. Of the system configuration shown in the present embodiment, the steps from the gasification step to the CO2 separation step are the same as in the first embodiment. The difference from Example 1 is that LNG is used as a cold heat source in the hydrogen purification process. When importing natural gas produced overseas, it is common to liquefy and transport it as LNG. When returning LNG to natural gas (CH4), a large amount of cold energy is generated. The feature of this embodiment is that this cold energy is used for hydrogen purification. Therefore, as a system configuration, in addition to the configuration of the first embodiment, a cold energy recovery process is added. In the cold heat recovery process, LNG is vaporized, and the cold heat generated at that time is recovered by another medium by indirect heat exchange. The medium that recovered the cold energy from LNG vaporization is supplied to the hydrogen purification process, and the hydrogen rich gas after CO2 separation is purified to high purity hydrogen. In addition, CH4 generated after LNG vaporization is supplied to the pipeline and used for household and industrial applications.

  The effect of this example is that when the imported LNG is used for household and industrial applications, it is generated when LNG is vaporized by recovering the cold heat that is generated when CH4 is vaporized and purifying hydrogen. It is in the point which can effectively use the cold heat.

(Example 3)
FIG. 3 shows another example of the system flow of the present invention. The basic configuration of this example is the same as that of Example 1, and the difference from Example 1 is that a CO2 recycling step for supplying CO2 separated in the CO2 separation step and the hydrogen purification step to the gasification step is provided. . When fossil fuel, especially coal, is supplied to the gasification process, the friction resistance in the supply pipe is large due to the solid matter, and it is difficult to supply the gasification process smoothly. Therefore, N2 produced in the air separation process is generally used as the carrier gas. Since N2 supplied for fossil fuel transportation in the gasification process is included in the hydrogen-rich gas after the CO2 separation process, it becomes a substance to be separated in the hydrogen purification process. When liquid nitrogen is used as a cooling medium in the hydrogen purification process, naturally, the boiling point of liquid nitrogen is equal to the freezing point of N2, and thus the separation efficiency of N2 is low.

  On the other hand, as shown in this example, when CO2 produced in the CO2 separation process or hydrogen purification process is used as the carrier gas, the CO2 concentration after the gasification process slightly increases, but it is separated in the CO2 separation process. The impact on the hydrogen purification process is small. However, since the CO2 concentration in the system increases, there is a concern that the CO conversion efficiency in the shift process is lowered due to equilibrium constraints. Therefore, it is necessary to take measures to increase the theoretical conversion rate by increasing the amount of steam added in the shift step or by lowering the reaction temperature. However, paying attention to the purpose of producing high-concentration hydrogen, it is considered that the load of the hydrogen purification process can be reduced more when CO2 is used than when N2 is used as the carrier gas.

Example 4
In this embodiment, an example of a hydrogen purification system according to the present invention is shown. An example of a system configuration diagram is shown in FIG. The hydrogen purification system in this example is composed of a compressor 1, an air separation facility 2, a gasification furnace 3, a washing tower 4, a shift reactor 5, a knockout drum 6, an H2S absorption tower 7, an H2S regeneration tower 8, and a CO2 absorption tower. 9. A CO2 flash drum 10 and a hydrogen purification equipment 11 are provided as main components. Gas compressed by supplying air to the compressor 1 is sent to the air separation facility 2 to separate oxygen and nitrogen. The separated oxygen and coal are sent to the gasification furnace 3, and a gasification gas mainly composed of CO and hydrogen is generated by a partial oxidation reaction. The gasification gas generated in the gasification furnace 3 is sent to the water washing tower 4 through the heat exchanger 12a and cleaned.

  Specifically, the water washing tower 4 removes impurities such as heavy metals and hydrogen halide in the product gas. Thereafter, the product gas washed in the water-washing tower 4 is sent to the shift reactor 5. At this time, the product gas is heated by the heat exchanger 12 a and the gas heater 13 and raised to the reaction temperature of the shift catalyst. By this heating, the inlet temperature of the product gas shift reactor 5 becomes 200 ° C. to 250 ° C. The main components of the product gas at the inlet of the shift reactor 5a during steady operation are CO and hydrogen. CO is about 60 vol% in a dry state and hydrogen is about 25 vol%. Water vapor is supplied at the inlet of the shift reactor 5a, and the CO shift reaction proceeds by the shift catalyst filled in each shift reactor. Coal gas contains trace amounts of COS and HCN. COS is converted by the reaction of Formula (3) and HCN is converted by the reaction of Formula (4). However, since it is a hydrolysis reaction similar to the shift reaction, it proceeds with the same catalyst as the shift catalyst. Therefore, COS and HCN converter are not provided separately, and CO, COS, and HCN are converted in the shift reactor.

  The gas discharged from each shift reactor 5a-5c is cooled by heat exchangers 7b-7d. Since the shift reaction is an exothermic reaction, the temperature at the reactor outlet is higher than that at the reactor inlet. In addition, because of the equilibrium, the CO conversion reaction is less likely to proceed at higher temperatures, so it is more efficient to adopt a system in which the reactor is configured in multiple stages and the gas is cooled between the reactors. Water in the gas after the final stage of the shift reactor (5c in this embodiment) is condensed and removed by the knockout drum 6. Thereafter, the gas is sent to the H2S absorption tower 7 to remove H2S by the absorbing solution. The gas after H2S removal is sent to the CO2 absorption tower 9, and CO2 in the gas is removed by the absorbing solution. The main component of the gas after CO2 removal is H2, which is used as a fuel for gas turbines if it is a power generation plant, and a chemical product production line or reducing gas if it is a plant for chemical production or iron making. Use as The CO2 absorbing solution is sent to the CO2 flash drum 10, and CO2 in the absorbing solution is regenerated by a depressurization operation using the solubility dependency of the solute gas partial pressure according to Henry's law.

  The regenerated CO2 is recovered by liquefaction and solidification. The H2S absorption liquid is sent to the H2S regeneration tower 8 and regenerated by heating with unused steam in the plant, for example. H2S discharged after heating regeneration is combusted and then plastered with calcium-based absorbent and limestone. Although the main component of the gas discharged from the CO2 absorption tower 9 is hydrogen, CO2 that has not been absorbed is contained in addition to CO and CH4 that cannot be removed by the absorbing solution as impurities. These gases are sent to the hydrogen purification facility 11 and are cryogenically separated by the cold heat of liquid nitrogen by-produced together with oxygen in the air separation facility 2 to obtain high purity hydrogen.

  In this embodiment, the water washing tower 4 is installed in the previous stage of the shift reactor 5 to remove heavy metals and hydrogen halide in the product gas. The catalyst used in the shift reactor 5 may be poisoned by the inflow of heavy metal or hydrogen halide, and the activity may be reduced. Therefore, it is necessary to remove heavy metals and hydrogen halides before the shift reactor 2.

  In this embodiment, as an apparatus for removing heavy metals and hydrogen halides, an example using a water washing tower which is a wet removal apparatus is shown, but a dry removal apparatus using an adsorbent or an absorbent material may be used. good. As the adsorbent and absorbent, porous materials such as activated carbon and zeolite can be used in addition to oxides, carbonates and hydroxides of alkali metals and alkaline earth metals.

  By using the dry removal device, the operation of cooling and raising the temperature of the product gas can be omitted, so that energy loss can be suppressed. However, when the water washing tower is used, it can be expected that entrained water vapor from the water washing tower is mixed with the product gas, and there is an advantage that the amount of water vapor supplied at the inlet of the shift reactor 2 can be reduced. As the catalyst charged in the shift reactor 5, a Co / Mo-based or Ni-Mo-based catalyst, which is a general sour shift catalyst, can be used. In addition, any shift catalyst having sulfur resistance can be used.

  Since the shift reaction is a hydrolysis reaction as shown in Formula (1), a water vapor supply pipe is installed in front of the shift reactor 5 so that a predetermined amount of water vapor can be constantly supplied to the product gas. . As the H2S absorption tower 7 and the CO2 absorption tower 9, either a physical absorption tower or a chemical absorption tower can be applied. As an example of the absorbing solution, selexol, lectisol, or the like can be used for physical absorption, and methyldiethanolamine (MDEA), ammonia, or the like can be used for chemical absorption. In this embodiment, the absorption liquid that has absorbed CO2 by the CO2 absorption tower 9 is a system that regenerates by the CO2 flash drum 10. In addition to the method using the flash drum, the regeneration of the absorbing solution may employ a heating regeneration method using a regeneration tower or a regeneration method using a combination of a flash drum and a regeneration tower. Moreover, although the process example which dehumidifies with the knockout drum 6 was shown as a dehumidification process in the present Example, the method of removing a water | moisture content with moisture absorbing materials, such as a molecular sieve and activated carbon, can also be applied besides this method.

(Example 5)
In this embodiment, an example of a hydrogen purification system according to the present invention is shown. An example of a system configuration diagram is shown in FIG. The basic structure of FIG. 5 is the same as that of Example 4, and the difference is that the hydrogen purification equipment 11 has a multistage structure such as 11a to 11c. As described above, the hydrogen-rich gas after the CO2 gas is finally separated into CO2 mainly contains CO2, CH4, and CO in addition to hydrogen. As described above, the boiling points of the respective gases are hydrogen -249 ° C, CO2 -79 ° C, CH4 -162 ° C, and CO -192 ° C.

  In the first hydrogen refining equipment 11a, by cooling to -80 ° C. or lower, for example, −100 ° C. with liquid nitrogen, only CO 2 in the gas is phase-changed (dry ice) and separated. Next, in the second hydrogen purification facility 11b, only CH4 is phase-changed (liquefied) and separated by cooling to a temperature between the boiling points of CH4 and CO, for example, -180 ° C. Finally, the third hydrogen purification facility 11c can cool to a temperature that is lower than the boiling point of CO and can be cooled with liquid nitrogen, for example, -195 ° C., and the final CO can be separated to finally obtain high-purity hydrogen.

(Example 6)
In this example, a test example of a shift catalyst that converts CO contained in gas into CO2 after partial oxidation of fossil fuel is shown. Specifically, for the sour shift catalyst targeted in the present invention, the results of evaluating the dependence of the CO conversion performance upon changing the amount of steam added on the catalyst type are shown. As described above, the present invention is characterized in that hydrogen purification is performed by a cryogenic separation method. If water is contained in the target gas to be subjected to cryogenic separation, the water may freeze in the target gas supply pipe near the hydrogen purification facility or inside the hydrogen purification facility, which may cause blockage of the pipe.

  Although it depends on the target value of CO conversion rate in the shift process, when the purpose is to obtain a conversion rate of 90% or higher, the water vapor, which is a reactant in the shift reaction of formula (1), exceeds the reaction equivalent ratio. It is necessary to add. As a result, moisture not used in the reaction is discharged from the shift process. Therefore, by selecting a catalyst that provides high CO conversion performance with a small amount of water vapor, it is possible not only to reduce the water discharged from the shift process, but also to reduce the load of the subsequent dehumidification process. It is thought that it can also contribute to the reduction of the amount of water discharged. As a result, troubles such as freezing and piping blockage in the hydrogen purification process as described above can be prevented.

  The test used the fixed bed flow type test device. An outline of the test apparatus is shown in FIG. The basic configuration of this apparatus is a gas supply system (mass flow controller 100), a water vapor supply system (water tank 101, plunger pump 102, water vaporizer 103), reaction tube 106, electric furnace 107, and trap tank 110. The reaction temperature in the reaction tube 104 was changed by the electric furnace 107. In the trap tank 110, moisture in the gas was condensed and trapped, and then the moisture in the gas was completely removed by the moisture absorption device 114 filled with magnesium perchlorate.

  CO, H 2, CH 4, CO 2, N 2, and H 2 S were adjusted by the mass flow controller 100 to be a predetermined flow rate and supplied to the reaction tube 106 as reaction gases simulating the product gas. In addition, the flow rate of water in the water tank 101 was adjusted by the plunger pump 102 and then vaporized by the water vaporizer 103 and supplied to the reaction tube 106.

    The reaction tube 106 was provided with an eye plate, glass wool 109 was laid on the eye plate, and the test catalyst 108 was filled on the upper part. Further, a Raschig ring 112 was filled as a flow regulating material on the upper part of the test catalyst 108.

  The performance evaluation test conditions of the test catalyst were as follows. Since the sour shift catalyst is filled in the reaction tube in an oxide state, it is necessary to reduce Mo by a reductive sulfidation operation shown in Formula (5) when used.

While circulating N ₂ , the temperature was raised until the catalyst reached 180 ° C. Then, switching to 7vol% H2 / N ₂ gas, the temperature was raised to 200 ° C.. After the temperature was stabilized, H2S was adjusted to 3 vol% and supplied. When it was confirmed that H2S was detected at the catalyst layer outlet, the temperature was raised to 320 ° C. at 1 ° C./min and maintained at 320 ° C. for 45 minutes, and then the reduction sulfurization treatment was terminated.

  The test gas used was a mixed gas of 5 kinds of CO 60 vol%, H2 20 vol%, CO2 5 vol%, CH4 1 vol%, N2 14 vol%, and 10% H2S / N2balance gas. The catalyst charge was 1400h-1 at a space velocity (SV) based on wet gas. Further, H2O as a reactant was supplied after adjusting so that H2O / CO (molar ratio) was 1.2, 1.5, and 1.8 mol / mol. The reaction temperature was 250 ° C. for each condition at the catalyst inlet temperature. The catalyst layer outlet gas was sampled, the CO concentration was measured with a gas chromatograph, and the CO conversion rate was calculated by the equation (6).

  The performances of Ni / Mo / TiO2 catalyst and Co / Mo / Al2O3 catalyst were compared as test catalysts. Each catalyst was prepared by the following procedure. First, titania (TiO2) and alumina (Al2O3) are selected as support components, ammonium heptamolybdate tetrahydrate, nickel nitrate hexahydrate and cobalt nitrate hexahydrate are supported metal components: Mo: M = 1 The mixture was mixed so that the metal molar ratio was 0.05: 0.05, further distilled water was added, and wet kneading was performed for 30 minutes in an automatic mortar. The above M represents Ni or Co. Next, after drying at 120 ° C. for 2 hours, baking was performed at 500 ° C. for 1 hour. The calcined catalyst is crushed in a mortar and pressure-molded at 500 kgf for 2 minutes with a pressure press. Finally, the molded catalyst was sized to 10-20 mesh to obtain a test catalyst.

  FIG. 7 shows the results of evaluating the dependency of the CO conversion performance on the amount of added water vapor with the prepared catalyst. Compared to the Co / Mo / Al2O3 catalyst, it was confirmed that the CO conversion of the Ni / Mo / TiO2 catalyst was uniformly high under each H2O / CO ratio condition. Therefore, when the Ni / Mo / TiO2 is applied to the shift reaction step, the amount of water vapor added to obtain the same CO conversion performance can be reduced, and as a result, the amount of water contained in the shift step outlet can be reduced. Therefore, it is judged that Ni / Mo / TiO2 is suitable as the catalyst applied to the present invention.

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Air separation equipment, 3 ... Gasification furnace, 4 ... Water washing tower, 5 ... Shift reactor, 6 ... Knockout drum, 7 ... H2S absorption tower, 8 ... H2S regeneration tower, 9 ... CO2 absorption tower DESCRIPTION OF SYMBOLS 10 ... CO2 flash drum, 11 ... Hydrogen purification equipment, 12 ... Heat exchanger, 13 ... Gas heater, 100 ... Mass flow controller, 101 ... Water tank, 102 ... Plunger pump, 103 ... Water vaporizer, 104 ... Line heater , 105 ... Mantle heater, 106 ... Reaction tube, 107 ... Electric furnace, 108 ... Test catalyst, 109 ... Glass wool, 110 ... Trap tank, 111 ... Moisture removal device, 112 ... Raschig ring

Claims (12)

Gasification process to gasify fossil fuel by partial oxidation with oxygen, gasification gas purification process, shift process to convert CO contained in gasification gas to water vapor by shift catalyst and convert to hydrogen and CO2 And a desulfurization process that removes H2S contained in the gas after the shift, a CO2 separation process that separates the hydrogen and CO2 produced in the shift process, and a hydrogen purification that purifies the gas after the CO2 separation and purifies the hydrogen. In a hydrogen production method comprising a process,
In the hydrogen purification step, a hydrogen production method is characterized in that a gas component other than hydrogen in the hydrogen-rich gas is phase-separated and separated into a high purity hydrogen by a cryogenic separation method using a cold medium.   2. The air separation step according to claim 1, further comprising an air separation step of separating air by cryogenic separation before the gasification step, supplying O2 generated in the air separation step as a combustion aid to the gasification step, A method for producing hydrogen, characterized in that the produced liquid nitrogen is supplied as a cooling medium to the hydrogen purification step.   2. The hydrogen production method according to claim 1, further comprising an LNG cold heat recovery step, wherein cold heat generated when LNG is vaporized is supplied to the hydrogen purification step.   4. The hydrogen production method according to claim 1, further comprising a dehumidifying step after the shift step.   5. The hydrogen production method according to claim 1, wherein the shift catalyst used in the shift step contains at least Ni, Mo, and Ti.   6. The method according to claim 1, further comprising a CO2 recycling step in which CO2 discharged from the CO2 separation step and / or the hydrogen purification step is used as a carrier gas when supplying fossil fuel to the gasification step. A method for producing hydrogen. Gasification furnace that gasifies fossil fuel by partial oxidation with oxygen, gasification gas purification equipment, and shift reaction in which CO contained in gasification gas is reacted with water vapor by a shift catalyst to convert it into hydrogen and CO2. , A desulfurization facility that removes H2S contained in the gas after the shift, a CO2 separation facility that separates the hydrogen and CO2 generated in the shift step, and a hydrogen that purifies the gas after the CO2 separation and purifies the hydrogen. In a hydrogen production apparatus equipped with a purification facility,
In the hydrogen purification equipment, a hydrogen production apparatus characterized in that a gas component other than hydrogen in the hydrogen-rich gas is phase-separated and separated into a high-purity hydrogen by a cryogenic separation method using a cold medium.   The gas separation furnace according to claim 7, further comprising an air separation facility for separating air by cryogenic separation at a stage preceding the gasification furnace, supplying O2 generated by the air separation facility to the gasification furnace as a combustor, A hydrogen production apparatus, wherein the produced liquid nitrogen is supplied to the hydrogen purification facility as a cold medium.   8. The hydrogen production apparatus according to claim 7, further comprising an LNG cold energy recovery facility, wherein cold energy generated when LNG is vaporized is supplied to the hydrogen purification facility.   The hydrogen production apparatus according to claim 7, further comprising a dehumidifying facility at a subsequent stage of the shift reactor.   11. The hydrogen production apparatus according to claim 7, wherein the shift catalyst charged in the shift reactor contains at least Ni, Mo, and Ti.   The CO2 recycling pipe according to any one of claims 7 to 11, wherein CO2 discharged from the CO2 separation facility and / or the hydrogen purification facility is used as a carrier gas when supplying fossil fuel to a gasification step. A hydrogen production apparatus characterized by

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